CA2701993A1 - Modular imaging device, module for this device, and method of implemented by this device - Google Patents

Abstract

The present invention relates to an imaging device comprising: an illumination module (1) comprising means for emitting at least one excitation beam; a scanning/injection module (2) comprising an image waveguide (3), the two ends of which, the proximal end (3a) and the distal end (3b) respectively, are connected via a plurality of optical fibres, and scanning/injection means (6) designed to inject the at least one excitation beam in turn into a fibre of the image waveguide (3) and then into the proximal side (3a) of said waveguide and a detection module (4) comprising means for detecting a light flux (14) collected at the distal end (3b) of the waveguide. At least either the illumination module (1) or the detection module (4) is optically conjugate with the scanning/injection module (2) via a conjugating optical fibre (5, 7). The use of conjugating fibres (5, 7) enables the maintenance, repair and updating of the device to be improved. It also enables modal filtering of the excitation beam to be carried out and ensures that the device is confocal.

Description

WO 2009/05363

2 PCT / FR2008 / 051845 Modular imaging device, module for this device and method thereof implemented by this device Technical area The present invention relates to a scanning imaging device proximal of a fiber optic strand. It also concerns a module for this device, and a method implemented by this device.
The field of the invention is in particular that of endoscopy and fibro-confocal microscopy.
State of the art Document WO 06 000 704 A1 describes a system microscopic fluorescence imaging by proximal scanning of a strand of optical fibers.
Such a system includes lasers emitting beams of excitation, a set of dichroic filters, separating plates, and of lenses that guide the excitation beams to means of sweeping that inject the excitation beams in turn into a fiber an image guide and the proximal side of the guide. The guide is arranged to guide the excitation beams to its distal end located in contact or near a sample. In response to the beams of excitation, the sample emits a luminous flux of response, collected by the distal end of the guide. The collected flow is guided along the guide and then by the scanning and injection means and the set of filters, blades, and lenses to a detector. A filter hole in front of the detector allows to reject the light that could have been coupled in the fibers of the guide adjacent to that carrying the excitation beams. Thus, only the part of the collected flow having been guided along the fiber carrying the excitation beams is imaged on the detector.
The optical alignment of the filter hole with respect to the position of the fiber from the guide on the proximal side of the guide is critical because it ensures the confocal character of the system. Such an alignment is complex to achieve, because the typical diameter of the fibers of the guide is a few micrometers.
This alignment depends in particular on all optical components located between the filter hole and the image guide.

The technical characteristics of some of the optical components of the system strongly depend on the wavelengths of the beams used, in particular the characteristics of the filters dichroic. A first problem with this system is that to change excitation beam wavelength, laser sources and filters dichroic are difficult to access, and it is generally preferable to replace the system entirely.
A second problem with such a system is that it is almost can not replace or move an optical component of the system or to add a new optical component to the system without having to realign the whole system. In particular, without realigning the system, its character confocal risk of being lost.
The objective of the present invention is to propose a device to solve some or all of the problems discussed above, as well as a method implemented in such a device.
Presentation of the invention This objective is achieved with an imaging device, comprising an illumination module comprising means for transmitting at least one excitation beam, a scanning and injection module comprising an image guide whose two ends respectively proximal and distal are connected by a plurality of optical fibers, and means of scanning and injection arranged to inject the at least one beam of excitement in turn in a fiber of the image guide and the side proximal of the guide, a detection module comprising means for detecting a light flux collected at the distal end of the guide, at least one of the illumination module and the detection module being optically conjugated to the scanning and injection module by an optical conjugation fiber.
In this document, two objects are said to be related or conjugated optically when at least one flux, signal or optical beam can be guided from one object to another. One of these objects may for example consist of one of the modules or one of the fibers of the device according to the invention.

-3-In this document, when two objects are optically conjugated by a main optical element (this main element comprising typically an optical fiber), there may be other optical elements intermediaries that conjugate the objects to the main optical element. The fiber of conjugation may comprise an illumination fiber, a fiber of detection, or a separation fiber that will be described later.
The optical fiber of conjugation can be, for a given position scanning and injection means, optically conjugated to a unique fiber of the guide.
The device according to the invention may comprise means for disconnect and reconnect the conjugation through the optical fiber of conjugation, like a connector.
The illumination module can be optically conjugated to the module scanning and injection by an optical fiber illumination. The fiber illumination optics can be arranged to perform a modal filtering of the at least one excitation beam, and is preferably an optical fiber singlemode. The transmission means may comprise several sources each emitting an excitation beam, and the illumination module can understand ways to multiplex the excitation beams in the optical fiber illumination. Each source can be conjugated optically to the multiplexing means by a source optical fiber, and the multiplexing means may comprise for example a fiber multiplexer fusing the cores of the source fibers, or means of multiplexed multiplexing system comprising, for example, acoustical systems optical multiplexing, or a multiplexer phasar type. Of preferably, the optical fiber of illumination is arranged to be conjugated optically in turn to a single fiber of the guide in which is injected in turn the at least one excitation beam by the means of sweep and injection.
Similarly, the detection module can be optically conjugated to the scanning and injection module by an optical fiber detection. The scanning and injection means can be arranged to guide the flow light collected to the detection module. Optical fiber detection can be arranged to perform spatial filtering of the collected light flux.
The optical fiber detection can be, for a given position of

-4-scanning and injection means, on the one hand optically conjugated to the fiber of the guide in which the scanning and injection means are arranged to inject the at least one excitation beam, and secondly arranged to reject light from the other fibers of the guide. The optical fiber detection is preferably a multimode optical fiber.
Preferably, the optical detection fiber is arranged to be optically conjugated in turn to a single fiber of the guide in which is injected in turn the at least one excitation beam by the scanning and injection means.
In general, the detection module may comprise means for demultiplexing in wavelength the collected luminous flux.
The detection means may comprise several detectors, each detector being arranged to detect a band of given wavelength of the demultiplexed stream.
The scanning and injection means can be arranged to guide the light flux collected at the distal end of the guide to the module detection device, and the device according to the invention may comprise means separation devices arranged to direct the at least one excitation beam towards the scanning and injection means, and to direct towards the module of detecting the light flux collected from the scanning means and injection. The separation means may comprise a filter dichroic, preferably multiband. The means of separation can also include a splitter cube, preferably a polarizing cube, the illumination module and the detection module then preferably especially for reflectance imaging of a sample. In a variant, the separation means are part of the scanner and injection. In another variant, the separation means are part of of a separation module, the detection module and the module illuminant being optically conjugated to the scanner and injection by the separation module and an optical separation fiber, this separating fiber conjugating the separation module to the module of scanning and injection, an illumination or detection fiber conjugate respectively the illumination or detection module to separation module. In one embodiment, the optical fiber of

-5-separation may comprise a single monomode or multimode fiber, depending on whether one seeks to optimize the quality of the beam respectively excitation or flow collected. In another embodiment, the fiber optical separation can include a two-core fiber, comprising two substantially concentric fiber cores, the first two hearts having a diameter smaller than the second of the two hearts, each of the cores can be either monomode or multimode. So preferential, the first core is monomode and arranged to carry the at least one excitation beam, and the second core is multimode and arranged to transport the collected luminous flux.

According to yet another aspect of the invention, a module is proposed for scanning and injection for a device according to the invention, said module comprising:
an image guide comprising two ends respectively proximal and distal connected by a plurality of optical fibers, conjugation means provided for optically conjugating the scanner and injection module to an illumination module comprising means for transmitting at least one beam of excitation, and to a detection module comprising means to detect a luminous flux collected at the distal end of the guide, scanning and injection means arranged to inject the at minus one excitation beam in turn in a fiber of the guide image and the proximal side of the guide, the conjugation means being arranged so that at least one of the illumination module and the detection module is optically conjugated to the scanning and injection module by an optical conjugation fiber.
The conjugation means may be arranged so that the fiber of conjugation is, for a given position scanning means and injection, optically conjugated to a single fiber of the guide.
In a variant, the conjugation fiber may be integral with the module. Thus, the conjugation means comprise the optical fiber of conjugation.
In another variant, the conjugation means can include means, such as a connector, for disconnecting fiber from

-6-conjugation of the scanner and injection and reconnect the fiber of conjugation to the scanning and injection module.
The conjugation means may comprise means for optically conjugate the scanning and injection module to the module of illumination by an optical fiber illumination, and these means of conjugation can be arranged so that the illumination fiber is, for a given position of the scanning and injection means, on the one hand optically conjugated to the fiber of the guide in which the means of scanning and injection are arranged to inject the at least one beam of excitation, and on the other hand not optically conjugated with the others fiber of the image guide.
In addition, the conjugation means may comprise means to optically conjugate the scanning and injection module to the module detection by an optical fiber detection, the scanning means and injection devices can be arranged to guide the light flux collected towards the detection module, and these means of conjugation can be arranged for the detection fiber to be, for a given position, means of scanning and injection, on the one hand optically conjugated to the fiber of the guide in which the scanning and injection means are arranged to inject the at least one excitation beam, and secondly not conjugate optically with the other fibers of the image guide.

According to yet another aspect of the invention, there is provided a method imaging, implemented in a device according to the invention, and comprising:
an emission, by an illumination module, of at least one beam excitation an injection, by a scanning and injection module, of the at least one an excitation beam in turn in a fiber of an image guide comprising two respectively proximal and distal ends connected by a plurality of optical fibers and on the proximal side of the guide, detection by a detection module of a luminous flux collected at the distal end of the guide, and

-7-an optical conjugation, by an optical conjugation fiber, of the illumination module and / or detection module with the module scanning and injection.
In this document, a linking step or optical conjugation between two objects comprises guiding at least one stream, signal or beam optical from one object to another. One of these objects may for example consist of one of the modules or one of the fibers of the device according to the invention.
Optical conjugation with the scanning and injection module can to understand an optical conjugation of the optical fiber of conjugation with a single fiber of the guide.
Optical conjugation with the scanning and injection module may include guiding the at least one excitation beam, the illumination module to the scanner and injection along of an optical fiber of illumination. The method according to the invention can include a modal filtering of the at least one excitation beam by the fiber of illumination. The method according to the invention may also comprise a Spatial overlay or multiplexing of multiple excitation beams in the fiber of illumination.
Optical conjugation with the scanning and injection module may include a guidance of the collected flow, the scanner and injection to the detection module along an optical fiber of detection. The method according to the invention may comprise a spatial filtering, detection fiber, of the collected flow, so that the optical fiber of detection is optically conjugated in turn to the fiber of the guide in which is injected in turn the at least one excitation beam.
The method according to the invention may further comprise a wavelength demultiplexing, by the detection module, of the flow collected light.
The method according to the invention may further comprise a guide, by the scanning and injection means, the luminous flux collected towards the detection module; guidance, by means of separation, from at least one excitation beam towards the scanning and injection means;
and guiding, by the separation means, the collected luminous flux from the scanning and injection means to the module of detection.

-8-By coupling between the fibers of an image guide, we mean a transmission, along the guide, of light between a first fiber of the guide and a second fiber of the guide next to the first fiber. Of Generally speaking, the description of the invention omits any coupling effects between the fibers of the image guide, especially when is said that the optical conjugation fiber is optically conjugated to a unique fiber of the guide: we do not consider the coupling between this unique fiber and guide fibers adjacent to this single fiber. So preferential, the image guide of the device, method, or module according to the invention is arranged so that there is substantially no coupling between the fibers of this guide.
Description of the Figures and Embodiments Other features and advantages of the invention will appear at the reading of the detailed description of embodiments and implementation in no way limiting, and the following appended drawings, where:
FIG. 1 is a schematic view of a device according to the invention, FIG. 2 is a more detailed view of a first embodiment of embodiment of the device according to the invention, FIG. 3 is a view of a second embodiment preferential device according to the invention, FIG. 4 is a view of a third embodiment of FIG.
device according to the invention, FIG. 5 is a view of a fourth embodiment device according to the invention, and FIG. 6 is a view of a fifth embodiment device according to the invention.
We will firstly describe, with reference to FIG.
according to the invention, the characteristics of which are common to the different embodiments which will be described later and which implement a method according to the invention.
The device comprises an illumination module 1, a module of scanning and injection 2, and a detection module 4. Typically, the guide includes several thousand fibers of a diameter of a few micrometers each.

-9 The illumination module 1 comprises means for transmitting at minus one excitation beam, and is optically conjugated to the scanning and injection 2 via an optical fiber 5. When the illumination module 1 emits the at least one excitation beam, this excitation beam is guided along the fiber illumination 5 to the scanning and injection module 2.
The scanning and injection module includes an image guide 3 comprising two respectively 3a and distal 3b proximal ends connected by a plurality of multimode optical fibers. The module sweep and injection 2 further comprises means 6 for sweeping and injecting the at least one excitation beam in turn into a fiber of the image guide 3 and the proximal side 3a of the guide. We hear in this document by position of the scanning and injection means a state scanning and injection means 6 for which these means are arranged to inject the at least one excitation beam into a fiber given in the guide 3, the means of scanning and injection taking successively several positions so as to sweep periodically all the fibers of the guide. This at least one excitation beam is then guided in this fiber of the guide to the distal end 3b of the guide 3.
The distal end 3b is intended to be placed in or in contact with a sample, and to collect a luminous flux emitted by the sample. The collected stream may for example include reflectance signals and / or fluorescence, emitted by the sample respectively by reflectance and / or by fluorescence in response to the at least one excitation beam that this sample received. By reflectance is meant light emission by broadcast or by retrocast. The guide 3 thus typically forms a endoscopic probe, the distal end 3b may or may not be equipped an optical head.
The scanning and injection module 2 is optically conjugated to detection module 4 via an optical detection fiber 7.
The luminous flux collected by the distal end 3b is guided up to the proximal end 3a, then is guided towards the entrance of the optical fiber of detection 7. The collected light flux is then guided along the fiber of detection 7 to the detection module 4.

-10-The detection module 4 comprises means for detecting the flow light collected at the distal end 3b.
A first function of the illumination and detection fibers 5 combining modules 1, 2, 4 is to play a role of bridge between these modules, and thus to separate the main internal functions of the device, that is to say, the functions of illumination, scanning and injection, and of detection, by associating each of these internal functions with one of the modules 1, 2, 4. Thus, these separate functions are simpler to repair.
The use of the fibers 5, 7 allows simple access to the components of the device, for example to replace an optical component inside of one of the modules 1, 2, 4 or to align components with each other optics inside one of the modules without risking optically misalign the entire device.
In addition, the ends of the fibers 5, 7 are fixed so removable to connectors, so that the conjugation between the module 1 and Scanner and Injection Module 2 via of the illumination fiber 5, and the conjugation between the detection module 4 and the scanning and injection module 2 via the fiber of detection 7 can be disconnected and reconnected. The different modules 1, 2, 4 of the device according to the invention can therefore be separated from the rest of the device. Thus, the separate functions are simpler to replace. One of the modules 1, 2, 4 can be replaced quickly, without having to replace the entire device which represents a benefit of cost, and without having to optically realign the modules together.
The fibered conjugations 5, 7 between modules 1, 2, 4, allow in in addition to adding other modules to the device according to the invention, or more generally to evolve the device without having to replace it in its entirety. For example, the illumination fiber 5 can be replaced by a set of optical components optically conjugated to the module of illumination 1 by an optical fiber and optically conjugated to the module scanning and injection 2 by another optical fiber, or replace the detection fiber 7 by a set of conjugated optical components optically to the detection module 4 by an optical fiber and conjugate optically to the scanning and injection module 2 by another fiber optical.

-11-Thus, architecture in the form of modules associated with functions separated and optically conjugated by optical fibers allows to reduce the costs and the manufacturing delays of the device according to the invention and improve the maintenance, repair or upgrade of the device according to the invention.
In addition, the optical fiber illumination 5 is an optical fiber monomode preferably Gaussian, the mode of the monomode fiber 5 being selected to effectively excite one or more modes of the guide 3.
Thus, the fiber 5 provides the at least one excitation beam with a large Gaussian monomode quality. In addition, the injection rate of the at least one excitation beam in the image guide 3 is optimal because the PSF (Point Spread Function or point spread function) at the injection into the guide is intended to correspond well to the fundamental mode of the fibers optical guide. So, another function of the illumination fiber is a modal filtering of the at least one excitation beam.
Finally, the optical illumination fiber 5 is arranged, for a position given means of scanning and injection, to be conjugated optically to a single fiber of the guide 3, more particularly to the fiber of the guide in which the scanning and injection means are arranged to inject the at least one excitation beam. For a given position scanning and injection means 6, the at least one excitation beam transported by fiber illumination 5 is injected only in a single fiber of the guide. In particular, the diameter of the illumination fiber 5 and the position of the end of the illumination fiber 5 facing the module of sweep and injection 2 depend on the diameter of the fibers of the guide 3, the position of the proximal end 3a of the guide and the characteristics of the optical components located between the illumination fiber 5 and the means of sweep and injection 6.
The detection optical fiber 7 is a multimode optical fiber. In effect, the luminous flux collected by the distal end 3b, emitted for example by reflectance or fluorescence, in general excites many fibers of the guide. Thus, the detection fiber 7 carries the stream luminous collected by guide 3 with almost no signal loss. So, another function of the detection fiber 7 is not to perform modal filtering on the flow collected by the guide 3.

-12-In addition, the optical detection fiber 7 is arranged, for a given position of the scanning and injection means, to be conjugated optically to a single fiber of the guide 3. In other words, for a given position of the scanning and injection means 6, the fiber of detection 7 conveys to the detection module only the part of the light flux collected at the distal end 3b having been guided along this single fiber of the guide 3. The detection fiber 7 makes it possible to reject the parts of the collected stream having been guided along the other fibers of the guide.
As for the illumination fiber 5, the diameter and the position of the end of the detection fiber 7 facing the scanner and injection must be adjusted. Preferably, the fiber optical detection is, for a given position scanning means and injection, optically conjugated to the fiber of the guide in which the scanning and injection means inject the at least one beam excitation. The detection fiber 7 therefore allows, for a given position scanning and injection means, to reject the parts of the stream collected having been guided along the fibers other than the one guiding the bundles excitation. Thus, the detection fiber 7 acts as a filtering hole.
The detection fiber 7 thus has a spatial filtering function of the collected stream at the distal end 3b. The detection fiber 7 makes it possible to select the fiber of the guide 3 used for illumination (that is, for the transportation of the minus one excitation beam) thus allowing the device to the invention to retain its confocal character. This confocal character is initially due to an optical conjugation of a point in the sample with only the guide fiber guiding an excitation beam exciting this point of the sample.
The scanning and injection means 6 are arranged to inject the at least one excitation beam in turn in a guide fiber image 3, so as to periodically scan all the fibers of the guide.
By alternately injecting the excitation beams into a fiber of the guide 3, the detection means of the detection module 4 detect in turn the light flux collected by the distal end 3b, guided along this fiber of the guide, and from a source point in the sample. When means sweeping and injection swept all the fibers of the guide, the means detected a set of source points of the sample,

- 13-that is, a whole field of view of the sample. The means of detection are connected to means to build, from this scan of the field of view, an image of the sample. The means of construction can construct a reflectance or fluorescence image of the sample, according to the nature of the signals of the collected luminous flux. The detection means are further connected to means for visualizing the constructed image. The size of the field of view depends on the number of fibers in the image guide, the diameter of these fibers, and possibly characteristics of the optical head located at the distal end of the guide if this head exists. Typically, the guide includes a few thousand fibers having a diameter of a few micrometers. The field of vision is so typically one or a few hundred micrometers apart. The device according to the invention is then particularly suitable for confocal fibro-fluorescence and / or reflectance microscopy.
We will now describe, with reference to FIG. 2, a first embodiment of device 101 according to the invention applied in particular to detection, quantification or fluorescence imaging. This mode embodiment having all the features of the device just being described with reference to FIG. 1, references 1 to 7 will not be described again.
The transmission means of the illumination module 1 comprise several sources of excitation 8, 9, 10. These sources of excitation are laser sources which each emit an excitation beam having a wavelength or wavelength band different from those of other excitation beams. The device 101 further comprises means for multiplexing the sources 8, 9, 10 within the optical fiber Thus, the optical illumination fiber 5 makes it possible to spatially superimpose all the excitation beams 11 at the input of the scanning and injection module 2.
Each source 8, 9, 10 is optically conjugated to a multiplexer 12 by a source fiber respectively 108, 109 or 110 which carries the excitation beam emitted by said source. The multiplexer 12 is a fiber multiplexer arranged to fuse the cores of the source fibers 108 to 110 in a single fiber whose illumination fiber 5 is the extension.

-14-At the input of the scanning and injection module 2, the excitation beams 11 are collimated by an optical system 13.
For the same reasons as for the illumination fiber 5, the fibers sources 108 to 110 are monomode fibers. Thus, the fibers 108 to 110 ensure each excitation beam a high single-mode quality Gaussian, and an optimal injection rate of each excitation beam in the image guide 3. Each source fiber thus allows modal filtering of an excitation beam.
The illumination module 1 comprises a housing inside which sources 8 to 10, source fibers 108 to 110 and the multiplexer 12. The illumination fiber 5 can be disconnected and reconnected from the housing of the illumination module 1 by means of a connector. Similarly, the source fiber 108 to 110 can be disconnected and reconnected from the source respectively 8 to 10, which allows replace this source and thus the wavelength or length band wave of the excitation beam emitted by this source.
The detection module 4 comprises means for demultiplexing in wavelength the luminous flux 14 collected at the distal end of the Guide 3. The demultiplexing means 15 comprise several filters dichroic 16a, 16b. Each dichroic filter 16a or 16b returns to a detector 17 or 18 a different band of wavelength of the stream 14.
Thus, each detector 17 or 18 is arranged to detect a band different wavelength of the stream 14, and makes it possible to image the sample at using fluorescence signals whose wavelength is included in this band and collected by the distal end 3b.
The detection means comprise at least one detector 17 or 18 per source 8 to 10 and therefore per beam wavelength band excitation. Each detector 17 or 18 is associated with a beam excitation. Indeed, the wavelength band of each detector 17 or 18 preferably corresponds to the emission band of a fluorophore excited at the wavelength or bandwidth band of the beam excitation associated with said detector. In the example shown in Figure 2, the device 101 comprises three sources 8 to 10 and four detectors 17 and 18, because several bands of wavelengths of stream 14 can be linked to the same wavelength or beam wavelength band

- 15-of excitation, said excitation beam being adaptable to excite several fluorophores.
Each dichroic filter 16a or 16b is associated with a fiber of demultiplexing 117 or 118 arranged to guide to the detector 17 or 18 the wavelength band returned by this dichroic filter. For the same reasons as the detection fiber 7, the demultiplexing fibers are multimode optical fibers. For reasons of photometry, and for an optical magnification equal to one of the set of optical components optically connecting each demultiplexing fiber with the fiber of detection 7, the demultiplexing fibers each have a larger diameter or equal to (preferably greater than) the diameter of the detection fiber 7, this which allows a greater optical alignment tolerance, and allows in besides collecting a maximum of flows that is to say to limit the losses Photometric. If the optical magnification is different from one, the fibers Each of the demultiplexers has a diameter greater than or equal to preferably greater than the diameter of the detection fiber 7 adjusted by this optical magnification.
The detection fiber 7 can be connected and disconnected from the module detection 4 by means of a connector. Similarly, the module detection includes means to disconnect and reconnect each multiplexing fiber 117, 118, which makes it possible to simply replace the detectors 17 and 18.
The scanning and injection module 2 comprises a housing inside which are grouped different optical systems 13, 19, the scanning and injection means 6, and means for separating the path optical excitation beams 11 of the optical path of the collected stream 14.
The image guide 3 is disconnectable from the scanner housing and injection 2, which allows in particular to change the type of guide 3 connected to the scanner and injection housing.
different types of guide 3, one can cite for example a guide whose fibers are singlemode, a guide whose fibers are multimode, a guide with an optical head at its distal end, a guide without an optical head at its distal end, a guide with a given number of fibers, a guide with a given fiber diameter, or a guide with a length given between its proximal end and its distal end.

-16-The separation means comprise a dichroic filter 20. The filter 20 is a multiband filter, that is, it can reflect many different wavelength bands and can transmit several more bands of wavelengths. In the example illustrated in FIG. 2, the filter 20 reflects bands corresponding to the wavelengths of the beams 11, and transmits bands corresponding to lengths wave of the collected stream 14 and the strips reflected by the filters 16a, 16b and detected by the detectors 17 and 18. It is also possible to realize the device 101 with a filter 20 which reflects bands corresponding to wavelengths of the collected stream 14 and the bands reflected by the filters 16a, 16b and detected by the detectors 17 and 18, and transmits corresponding to the wavelengths of the excitation beams, provided to exchange the positions of the illumination fiber 5 and the module 1 with the positions of the detection fiber 7 and the module of detection 4 and to switch the optical systems 13 and 19.
The excitation light beams 11 guided along the fiber 5 and collimated by the optical system 13 are directed by the separation means to the scanning and injection means.
scanning and injection means 6 comprise two movable mirrors 6a allowing two-dimensional scanning in the plane of the entrance surface the proximal end of the guide, and an optical system 6b. Mirrors 6a inject the excitation beams alternately into a fiber of the picture guide. Before entering guide 3, the excitation beams pass through the optical system 6b which focuses them on the end proximal of the guide 3.
Conversely, the collected flow 14 is collimated by the optical system 6b then is directed by the moving mirrors 6a towards the detection module 4.
Between the moving mirrors 6a and the detection module 4, the collected flow 14 passes through the means of separation, is focused by the system optical 19 input of the detection fiber 7, then is guided along the detection fiber 7 to the detection module 4.
The illumination fiber 5 can be disconnected and reconnected from the scanner housing and injection 2 by means of a connector.
Likewise, the detection fiber 7 can be disconnected and reconnected from the scanner housing and injection 2 by means of a connector.

- 17-A problem of the device 101 is the spectral characteristic of the filter dichroic 20 located inside the housing of the scanner and injection 2, in particular the wavelength bands which it must transmit or reflect, depend on the wavelengths of the beams of excitation and the flow collected. A wavelength change of one of the excitation beams imposes to change the multiband filter 20, while this one is complicated to specify, to manufacture and to align optically in the scanning and injection module.
We will now describe, with reference to FIG.
embodiment of device 102 according to the invention which allows solve this problem. The device 102 is an embodiment preferential device according to the invention implementing a mode of preferential embodiment of the method according to the invention. Device 102 does not will be described that for its differences from the device 101 described in reference in Figure 2. In particular, references 1 to 19, 108 to 110, 117 and 118 will not be described again. The device 102 allows in particular the detection of fluorescence or reflectance signals collected at the distal end of the guide, and quantifies these signals and / or build images of the sample by fluorescence and by reflectance from these signals.
In the device 102, the separation means of the module of scan and injection 2 consist of a polarizing cube 21 which replaces the dichroic multiband filter. The polarizing cube 21 reflects beams having a first polarization, and transmits the beams having a polarization orthogonal to the first polarization. All beams excitation 11 have the same polarization. The parasitic reflections of excitation beams, for example at the scanning means and injection 6 or guide 3, have retained the same polarization as that of excitation beams. On the other hand, the collected flow 14 coming from the part distal of the guide 3 has lost the state of polarization of the excitation beams, and therefore includes signals having one or more polarizations random in time. The polarizing cube 21 is arranged to direct the excitation beams 11 to the scanning and injection means 6, and to direct the collected luminous flux 14 towards the detection module 4. On In the example of FIG. 3, the cube 21 reflects the excitation beams 11

- 18-as well as parasitic reflections, and transmits at least part of the flow collected 14. It is also possible to realize the device 102 with a cube 21 which at least partly reflects the collected stream 14, and transmits the beams of excitation, provided that the positions of the illumination fiber are exchanged and the illumination module 1 with the positions of the detection fiber 7 and of the detection module 4. Thus, the cube 21 makes it possible to separate between on the one hand the excitation beams and parasitic reflections having retained the polarization of the excitation beams, and on the other hand the flux collected 14 from the distal portion of the guide 3.
One of the filters 16a of the detection module 4 is designed to direct to the detector 18 a wavelength band of the collected stream 14 including the wavelength or wavelength band of one of the laser sources 8. Thus, the detector 18 and the laser source 8 can be used for reflectance imaging of the sample located at the level of the distal end of the guide. This is only possible because there is a rejection of parasitic reflections by the cube 21. The other filters 16b of the detection module 4 and the associated sensors 17 allow, as for the first embodiment, to quantify fluorescence from the sample or to make imaging of fluorescence of the sample.
The use of the cube 21 presents a disadvantage compared to first embodiment of the device according to the invention. Indeed, the use of the cube 21 causes losses of intensity of the collected flow 14, and in particular, fluorescence signal intensity losses. Indeed, if we consider that the cube directs all the intensity of the excitation beams 11 towards the scanning and injection means 6 because of their polarization, the collected flow 14 is partially reflected and partly transmitted by the cube because it does not have a single polarization. The collected stream 14 is therefore directed in part towards the detection module 4. Typically, loses 50% of the intensity of the collected stream 14 and directed to the module of 4. Thus, the sensitivity of the device 102 is decreased.
Moreover, in order not to lose intensity of the excitation beams 11 directed towards the scanning and injection means, all the fibers guiding the excitation beams 11 to the scanning and injection means 6 (i.e., the source fibers 108 to 110 and the illumination fiber 5) are

-19-polarization-maintaining fibers, which leads to an additional cost of realization and a specific setting.
We will now describe, with reference to FIG.
embodiment of device 103 according to the invention. Device 103 does not will be described that for its differences from the device 101 described in reference in Figure 2. In particular, references 1 to 20, 108 to 110, 117 and 118 will not be described again. The device 102 allows in particular the detection of fluorescence and / or reflectance signals collected at the distal end of the guide, and quantifies these signals and build, from these signals, images of the sample by fluorescence and reflectance.
The device 103 further comprises a second module 201 and a second detection module 204. The second illumination module 201 differs from the illumination module 1 in that it includes only one source emitting an excitation beam, and does not include multiplexing means. The second module of detection 204 differs from the detection module 4 in that it does not include only one detector, no filters and no means of demultiplexing.
The second illumination module 201 and the detection module 204 are optically conjugated to the scanning and injection means 6 of the same way as the illumination and detection modules of the second Embodiment 102 illustrated in Figure 3. Indeed, the second illumination module 201 is optically conjugated to the scanner and injection 2 through a second optical fiber monomode illumination 205 with polarization maintenance, the second detection module of 204 is optically conjugated to the module of scanning and injection 2 via a second optical fiber of multimode detection 207, and scanner and injection 2 comprises the polarizing cube 21 already described with reference to FIG.
cube 21 is arranged to direct on the one hand the excitation beam of the second illumination module 201 to the scanning means and 6 and to direct the collected luminous flux 14 in part towards the second detection module 204.
The dichroic filter 20 and the polarizing cube 21 are conjugated optically to the scanning and injection means 6 by the same blade

-20-separator 22. The separating blade 22 is arranged to direct towards the scanning and injection means 6 the excitation beams from the first or second illumination module. The separating blade 22 is further arranged to direct the collected stream 14 in part to the first detection module 4 and partly to the second detection module 204. The part of the flow 14 directed towards the first detection module 4 includes the wavelength bands of stream 14 directed by the filters 16a, 16b to the detectors 17, 18. The portion of the flow 14 directed towards the second detection module 204 includes the wavelength or band wavelength of the excitation beam emitted by the second module 201, so that the detector of the second module of detection 204 is arranged to detect within the collected stream 14 a signal reflectance emitted by the sample in response to the excitation beam of the second illumination module 201. Thus, the second module of detection 204 makes it possible to perform reflectance imaging of the sample. Indeed, parasitic reflections of the excitation beam of the second illumination module 201 operate in particular in the means scanning and injection, but the rejection of these parasitic reflections is provided by the polarizing cube 21. The device 103 thus makes it possible to fibro-confocal microscopy, simultaneous imaging of reflectance (and thus morphological imaging), thanks to the second illumination module and the second detection module, and imaging fluorescence (and therefore functional imaging), thanks to the first illumination module and the first detection module, of the sample located near or in contact with the distal end of the guide 3.
In a first variant, the scanning and injection means 6 are arranged, during its different successive positions, to optically conjugate the first optical fiber illumination 5, the first optical fiber detection 7, the second optical fiber 205, and the second detection optical fiber 207 in turn with a single fiber of the image guide 3, so as to sweep periodically all the fibers of the guide:
the first optical illumination fiber 5 is arranged, for a given position of the scanning and injection means (i.e.

-21-given instant), to be optically conjugated to a unique first fiber of the guide 3.
the first detection optical fiber 7 is arranged, for this same position given means of scanning and injection, to be optically conjugated to this first single fiber of the guide 3, the second illumination optical fiber 205 is arranged, for this same position given means of scanning and injection, to be optically conjugated to this first single fiber of the guide 3, and the second detection optical fiber 207 is arranged, for this same position given means of scanning and injection, to be optically conjugated to this first single fiber of the guide 3.
This first variant makes it possible to simplify the construction of reflectance and fluorescence images.
In a second variant, the scanning and injection means 6 are arranged, during its different successive positions, to optically conjugate the first optical fiber illumination 5 and the first detection optical fiber 7 in turn with a single fiber of the image guide 3 so as to periodically sweep all the fibers of the guide, and to optically conjugate the second optical fiber 205 and the second sensing optical fiber 207 in turn with another single fiber of the image guide 3 so as to sweep periodically all the fibers of the guide:
the first optical illumination fiber 5 is arranged, for a given position of the scanning and injection means (i.e.
given instant), to be optically conjugated to a unique first fiber of the guide 3.
the first detection optical fiber 7 is arranged, for this same position given means of scanning and injection, to be optically conjugated to this first single fiber of the guide 3, the second illumination optical fiber 205 is arranged, for this same position given means of scanning and injection, to be optically conjugated to a second single fiber of the guide 3, preferably adjacent to the first single fiber, and

-22-the second detection optical fiber 207 is arranged, for this same position given means of scanning and injection, to be optically conjugated to this second single fiber of the guide 3.
This second variant makes it possible to reduce the reflections even more interference between the reflectance signals and the fluorescence signals, but requires a temporal registration of the reflectance and fluorescence built.
We will now describe, with reference to FIG.
embodiment of device 104 according to the invention, applied in particular to the detection, quantification or fluorescence imaging of the sample. The device 104 will only be described for its differences by relative to the device 101 described with reference to FIG. 2. In particular, the references 1 to 20, 108 to 110, 117 and 118 will not be again described.
Unlike the first embodiment 101 described in FIG. 2, the means 20 for separating the optical path from excitation beams 11 of the optical path of the collected stream 14, and the optical systems 13 and 19 are located outside the scanner and injection 2. Thus, the scanner and injection is totally independent of the wavelengths of the excitation beams 11 and the flux collected 14.
Indeed, the device 104 comprises a separation module 23. The separation module 23 comprises a housing inside which are optical systems 13, 19, another optical system 24, and the dichroic filter 20.
The illumination fiber 5 can be disconnected and reconnected no more to the case of the scanner and injection, but to the case of the separation module 23 by means of a connector. Similarly, the fiber of detection 7 can be disconnected and reconnected no longer to the box of the scanning and injection module, but to the separation module housing

23 by means of a connector. The separation module 23 and the module scanning and injection 2 are optically conjugated by an optical fiber two hearts 25.
The two-core fiber 25 comprises two fiber cores substantially concentric, the first core being monomode and arranged for transporting the excitation beams 11, the second core being multimode and arranged to carry the collected luminous flux 14. One of the ends of the two-core fiber 25 can be disconnected and reconnected from the housing of the separation module 23 by means of a connector, and the second end of the two-core fiber 25 can be disconnected and reconnected from the scanner and injection housing 2 by means of a connector.
As in the first embodiment, the illumination fiber 5 is arranged to guide the excitation light beams 11. The system 13 is arranged to collimate the excitation beams guided by the illumination fiber 5. The dichroic filter 20 is arranged to direct the excitation beams 11 collimated towards the scanning means and injection 6, and to direct the collected flow 14 to the detection module 4.
Unlike the first embodiment, the dichroic filter 20 is arranged to direct the excitation beams 11 to the optical system

24 and the two-core fiber 25. The optical system 24 is arranged to focus the excitation beams 11 at the input of the two-core fiber 25 to the scanning and injection module 2. The two-core fiber 25 is arranged to guide the excitation beams 11 along its first core to the scanner and injection 2. In addition, fiber to two hearts is arranged to guide the collected flow 14 along its second core to the separation module 23. The optical system 24 is arranged to collimate the collected flow 14, and the dichroic filter 20 is arranged for direct the collected stream 14 and collimated to the detection fiber 7. The optical system 19 is arranged to focus the collected stream 14 and reflected by the filter 20 at the input of the detection fiber 7 to the module of detection 4.
The scanner and injection module 2 further comprises a optical system 26 arranged to collimate the excitation beams 11 into from the separation module 23 and directed to the means of scanning and injection 6, and to focus the collected stream 14 at the input of the two-core fiber 25 to the separation module 23.
In the device 104, the illumination module 1 is conjugated optically to the scanning and injection module 2 via the optical fiber illumination 5 and the two-core fiber 25. Similarly, the detection module 4 is optically conjugated to the scanner and injection 2 via the detection optical fiber 7 and the two-core fiber 25.
The first core of the two-core fiber being a fiber Gaussian monomode, it ensures the excitation beam a high quality Gaussian monomode, and an optimal beam injection rate 11 in the image guide 3. Thus, the two-core fiber has a modal filtering function of the excitation beams. In addition, the second heart being multimode, the two-core fiber has the function of not perform modal filtering on the collected stream 14, for the same reasons that the detection fiber 7.
Finally, the two-core fiber 25 is arranged for a position given scanning and injection means 6, to be conjugated optically to a single fiber of the guide 3. In fact, for a position given means of scanning and injection 6, the excitation beams 11 transported by the two-core fiber 25 are only injected into one single fiber of the guide, and the diameter and position of the second heart are calculated so that the second heart carries a collected luminous flux 14 having been guided only along this single fiber of the guide.
Thus, the two-core fiber 25 has a spatial filtering function of the stream collected 14, and gives the device 104 its confocal character.
The technical characteristics of the dichroic filter 20 are dependent on the wavelengths of the excitation beams 11 and the flux collected 14. A change in wavelength of one of the beams of excitation requires the replacement of the multiband filter 20. This change can be easily achieved by replacing the separation module 23 with a new separation module including a new dichroic filter 20, without having to optically realign the device 104 or one of the modules of the device 104.
We will finally describe, with reference to FIG. 6, a fifth mode of embodiment of device 105 according to the invention. The device 105 will not be described that for its differences from the device 104 described with reference to In particular, references 1 to 19, 21, 23 to 26, 108 to 110, 117 and 118 will not be described again. The device 105 allows

-25-in particular the detection of fluorescence or reflectance signals collected at the distal end of the guide, and allows to build images of the sample by fluorescence and reflectance.
In the device 105, the dichroic filter 20 of the separation module 23 has been replaced by the polarizing cube 21 described with reference to FIG.
As for the second embodiment of the device according to the invention, the polarizing cube 21 makes it possible to use one of the detectors 18 and one of the laser sources 8 for reflectance imaging. Indeed, the cube polarizer 21 provides, as described with reference to FIGS. 3 and 4, the rejection of parasitic reflections from the excitation beam of the laser source 8 used for reflectance. To avoid losing beam intensity of excitation 11 directed towards the scanning and injection means, all the fibers guiding the excitation beams 11 to the scanning means and injection 6 (i.e. the source fibers 108 to 110, the fiber 5 and the first core of the two-core fiber 25) are polarization maintaining fibers, which leads to additional cost of implementation.
The typical dimensions of elements of the different modes of realization just described are:
- core diameter of the detection fiber 7 50 micrometers, core diameter of the demultiplexing fibers 117, 118:
62.5 micrometers, core diameter of the illumination fiber 5 micrometers, diameter of the single-mode core of the two-core fiber 25 4 micrometers, and diameter of the multimode core of the two-core fiber 25 10 micrometers Of course, the invention is not limited to the examples that come to be described and many adjustments can be made to these examples without departing from the scope of the invention.
In particular, a source of an excitation beam may be a multi-wavelength laser, that is to say a laser emitting simultaneously several wavelengths or bands of wavelengths.

-26-Similarly, a source of an excitation beam may be a laser adjustable wavelength, an Electro Luminescent Diode (LED), a broad spectrum lamp or a super continuum.
In addition, the demultiplexing means may for example be phasar type or be fibered, and include for example a junction merging the cores of the demultiplexing fibers 117, 118 into the core of the detection fiber 7. The description is in no way restrictive concerning the number of sources per illumination module and the number of detectors by detection module.
The device according to the invention may comprise several multiplexers in series and / or in parallel between the excitation sources and the scanning and injection module.
According to the invention, the fibers of the image guide can be all multimodes, or any single mode, or may comprise a mixture of multimode and singlemode fibers.
Finally, at least one of the dichroic filters of a detection module or the dichroic filter of a separation module can be a filter dynamical dichroic dynamics of which one can dynamically control wavelength that it reflects or transmits. Such a dichroic filter dynamic can for example include an acousto-optic modulator or an electro-optical modulator, a command applied to the modulator to control the wavelength bands.

Claims (32)

An imaging device (101-105), comprising an illumination module (1) comprising means for transmitting at least one excitation beam (11), a scanning and injection module (2) comprising a guide of image (3), of which two respectively proximal ends (3a) and (3b) are connected by a plurality of optical fibers, and scanning and injection means (6) arranged to inject the at minus one excitation beam in turn in a fiber of the guide images (3) and the proximal side (3a) of the guide, a detection module (4) comprising means (15-18, 117, 118) for detecting a luminous flux (14) collected at the distal end (3b) of the guide, at least one of the illumination module (1) and the detection module (4) being optically conjugated to the scanning and injection module (2) by an optical conjugation fiber (5, 7, 25). 2. Device according to claim 1, characterized in that the fiber optical conjugation (5, 7, 25) is, for a given position of scanning and injection means (6), optically conjugated to a single fiber guide (3). 3. Device according to claim 1 or 2, characterized in that includes means for disconnecting and reconnecting the conjugation by the optical conjugation fiber (5, 7, 25). 4. Device according to any one of claims 1 to 3, characterized in that the illumination module (1) is conjugated optically to the scanning and injection module (2) by a fiber illumination optics (5). 5. Device according to claim 4, characterized in that the fiber illumination optics (5) is arranged to perform modal filtering of the at least one excitation beam, and is preferably a fiber single mode optical. 6. Device according to claim 4 or 5, characterized in that the means of transmission include several sources (8-10) each an excitation beam, and in that the module of illumination comprises means for multiplexing (12) the excitation beams (11) in the optical illumination fiber (5). 7. Device according to claim 6, characterized in that each source (8-10) is optically conjugated to the means of multiplexing (12) by a source optical fiber (108-110), and that the multiplexing means comprise a fiber multiplexer (12) fusing the hearts of the source fibers (108-110). 8. Device according to any one of claims 1 to 7, characterized in that the detection module (4) is conjugated optically to the scanning and injection module (2) by a fiber optical detection (7). 9. Device according to claim 8, characterized in that the means of scanning and injection (6) are arranged to guide the flow collected light (14) to the detection module (4). 10. Device according to claim 9, characterized in that the fiber detection optics (7) is arranged to perform spatial filtering collected light flux, and is, for a given position of scanning and injection means (6), on the one hand combined optically to the fiber of the guide in which the means of sweep and injection (6) are arranged to inject the at least one excitation beam (11), and on the other hand arranged to reject the light from the other fibers of the guide (3). 11. Device according to any one of claims 8 to 10, characterized in that the detection optical fiber (7) is a fiber multimode optical. 12. Device according to any one of claims 8 to 11, characterized in that the detection module (4) comprises means (15) for demultiplexing the luminous flux in wavelength collected (14). 13. Device according to claim 12, characterized in that the detection means (4) comprise a plurality of detectors (17, 18), each detector being arranged to detect a band of length given wave of the demultiplexed stream (14). 14. Device according to any one of claims 1 to 13, characterized in that the scanning and injection means are arranged to guide the collected light flux (14) at the end distal from the guide to the detection module (4), and in that comprises separating means (20, 21) arranged to direct the at least one excitation beam (11) towards the scanning means and injection (6), and to direct to the detection module (4) the collected light flux (14) from the scanning means and injection (6). 15. Device according to claim 14, characterized in that the separation means comprise a dichroic filter (20), multiband preference. Device according to claim 14, characterized in that the means of separation comprise a separator cube (21), the illumination module (1) and the detection module being preferably provided for reflectance imaging. Device according to one of claims 14 to 16, characterized in that the separating means (20, 21) are part of of the scanning and injection module (2). 18. Device according to any one of claims 14 to 16, characterized in that the separating means (20, 21) are part of separation module (23), the detection module (4) and the illumination module (1) being optically conjugated to the module of sweeping and injection (2) by the separation module (23) and a optical separation fiber (25) conjugating the separation module (23) to the scanning and injection module (2). 19. Device according to claim 18, characterized in that the fiber optical separation (25) comprises two fiber cores substantially concentric, the first core being monomode and arranged to carry the at least one excitation beam (11), the second core being multimode and arranged to carry the stream collected light (14). 20. Scan and injection module for a device according to one of preceding claims, comprising:
an image guide (3) comprising two ends respectively proximal (3a) and distal (3b) connected by a plurality of fibers optical, conjugation means provided for optically conjugating the scanning and injection module to an illumination module (1) comprising means for transmitting at least one beam excitation circuit (11), and to a detection module (4) comprising means for detecting a light flux (14) collected at the end distal (3b) of the guide, scanning and injection means arranged to inject the at minus one excitation beam (11) in turn in a fiber of image guide (3) and the proximal (3a) side of the guide, the conjugation means being arranged so that at least one of the illumination module (1) and the detection module (4) is conjugated optically to the scanning and injection module (2) by a fiber optical conjugation (5, 7, 25). 21. Scan and injection module according to claim 20, characterized in that the conjugating means are arranged to that the conjugation fiber (5, 7, 25) is, for a given position scanning and injection means, optically conjugated to a single fiber guide (3). 22. Module according to claim 20 or 21, characterized in that the means of conjugation include the conjugation fiber (5, 7, 25) which is integral with the module. 23. Module according to claim 20 or 21, characterized in that the mating means includes means for disconnecting and reconnect the conjugation fiber (5, 7, 25) of the sweep and injection. 24. Scanning and injection module according to any one of Claims 20 to 23, characterized in that the means for conjugation include means to optically conjugate the scanning and injection module at the illumination module (1) by an optical fiber for illumination (5), and that these means of conjugation are arranged so that the illumination fiber is, for a given position of the scanning and injection means (6), optically conjugated to the fiber of the guide in which the means scanning and injection are arranged to inject the at least one excitation beam (11). 25. Scanning and injection module according to any one of Claims 20 to 24, characterized in that the means for conjugation include means to optically conjugate the scanning and injection module to the detection module by a optical fiber detection (7), in that the scanning means and injectors are arranged to guide the collected luminous flux (14) to the detection module (4), and that these means of conjugation are arranged so that the detection fiber is, for a given position of the scanning and injection means (6), optically conjugated to the fiber of the guide in which the means scanning and injection are arranged to inject the at least one excitation beam (11). 26. Imaging method, comprising an emission, by an illumination module (1), of at least one excitation beam (11), an injection, by a scanning and injection module (2), of the minus one excitation beam (11) in turn in a fiber of a image guide (3) comprising two ends respectively proximal (3a) and distal (3b) connected by a plurality of fibers optical and proximal (3a) of the guide, detection by a detection module (4) of a luminous flux (14) collected at the distal end (3b) of the guide, and an optical conjugation, by an optical conjugation fiber (5, 7, 25), the illumination module (1) and / or the detection module (4) with the scanning and injection module (2). 27. The method of claim 26, characterized in that the optical conjugation with scanning and injection module (2) comprises an optical conjugation of the optical conjugation fiber (5, 7, 25) with a single fiber of the guide (3). 28. The method of claim 26 or 27, characterized in that the optical conjugation with the scanning and injection module comprises guiding the at least one excitation beam (11), the illumination module (1) to the scanning and injection module (2) along an optical illumination fiber (5). 29. The method of claim 28, characterized in that it comprises a modal filtering of the at least one excitation beam (11) by the illumination fiber (5). 30. The method of claim 28 or 29, characterized in that includes a spatial overlay of multiple beams of excitation (11) in the illumination fiber (5). 31. Method according to any one of claims 26 to 30, characterized in that the optical conjugation with the module of scanning and injection comprises guiding the collected flow (14), the scanning and injection module (2) to the detection module (4) along a detection optical fiber (7). 32. The method of claim 31, characterized in that it comprises a spatial filtering, by the detection fiber, of the collected flow (14), so that the optical detection fiber (7) is conjugated optically in turn to the fiber of the guide (3) in which is injected in turn the at least one excitation beam (11).